The present invention relates to a dispensing device for liquids, more particularly for filling up cavities of titration plates, with a distributing pipe connected via piping to a pump and from which extend radially at least two, preferably eight, charging pipes.
Medical laboratory technology makes use of the Elisa (Enzyme Linked ImmunoSorbent Assay) method or the various processes of this system, for instance for measuring antigens and/or antibodies. As an example, to measure antigens in a first process step, antibodies are absorbed on the titration plate, the titration plate is then washed, whereupon in a further process step a residual solution containing the antigen is added. This is followed by another washing, after which enzyme-marked specific antibodies are added to the titration plate, again followed by washing on the titration plate and addition of the enzyme substrate.
The actual measuring is effected by means of a photometer.
The microtitration plates currently in use comprise 96 cavities, each one of which corresponds practically to a cuvette.
The dispensing devices of known construction are capable of filling up eight cavities at a time.
One of the main problems encountered is the fact that the charge must be as constant as possible for each cavity and further that both the formation of air bubbles and post-dripping must be prevented with the highest degree of assurance.
The uniform delivery problem is rendered more difficult by the fact that one and the same device must be able to deliver liquids with different viscosities in different test operations.
With the conventional variable-stroke piston pump or membrane pump, a delivery equalization accurate to 5% is achieved. This is to be significantly improved by the invention.